Inorganic or hybrid inorganic/organic layers have been used in thin films for electrical, packaging and decorative applications. These layers can provide desired properties such as mechanical strength, thermal resistance, chemical resistance, abrasion resistance, moisture barriers, and oxygen barriers. Highly transparent multilayer barrier coatings have also been developed to protect sensitive materials from damage due to water vapor. The moisture sensitive materials can be electronic components such as organic, inorganic, and hybrid organic/inorganic semiconductor devices. The multilayer barrier coatings can be deposited directly on the moisture sensitive material, or can be deposited on a flexible transparent substrate such as a polymer film.
Multilayer barrier coatings can be prepared by a variety of production methods. These methods include liquid coating techniques such as solution coating, roll coating, dip coating, spray coating, spin coating; and dry coating techniques such as Chemical Vapor Deposition (CVD), Plasma Enhanced Chemical Vapor Deposition (PECVD), sputtering and vacuum processes for thermal evaporation of solid materials. One approach for multilayer barrier coatings has been to produce multilayer oxide coatings, such as aluminum oxide or silicon oxide, interspersed with thin polymer film protective layers. Each oxide/polymer film pair is often referred to as a “dyad”, and the alternating oxide/polymer multilayer construction can contain several dyads to provide adequate protection from moisture and oxygen. Examples of such transparent multilayer barrier coatings and processes can be found, for example, in U.S. Pat. No. 5,440,446 (Shaw et al.); U.S. Pat. No. 5,877,895 (Shaw et al.); U.S. Pat. No. 6,010,751 (Shaw et al.); U.S. Pat. No. 7,018,713 (Padiyath et al.); and U.S. Pat. No. 6,413,645 (Graff et al.).